The United Nations is hoping a 72-hour ceasefire in Yemen due to start on Wednesday will allow vital aid to reach parts of the country that have been cut off by months of fighting and are in dire humanitarian need.

A ceasefire between warring factions in Yemen will begin at 2359 local time (2059 GMT) on Wednesday, the UN said on Monday, raising hopes of an end to a war in the Arab world’s poorest country that has killed thousands of civilians and left people starving.

Aid agencies may try during the ceasefire to reach families trapped in towns and villages where fighting – and a sea, air and land blockade imposed by a Saudi-led Arab coalition fighting in Yemen – has left people short of food and in need of vital medical supplies.

“Hopefully this nationwide cessation will provide humanitarian agencies and organizations the opportunity to respond in areas that have been cut off or are hard to reach in all of Yemen,” Jamie McGoldrick, the U.N.’s Yemen Humanitarian Coordinator, told Reuters.

McGoldrick said he hoped the cessation of hostilities would be extended and would herald a resumption of peace talks that collapsed in August.

Saudi Arabia and several Gulf Arab allies have carried out air strikes and deployed troops in Yemen in support of the exiled Yemeni government which was toppled by the Iran-aligned Houthis in 2015.

The Houthis and their allies, forces loyal to former President Ali Abdullah Saleh, hold most of Yemen’s northern half, while forces loyal to the Saudi-backed Yemeni government share control of the rest of the country with local tribes.